Metallic materials are processed for various engineering projects in several ways. The metallic materials may be alloyed by the addition of other elements to control functional properties. The properties that may be changed by alloying are: 1) mechanical properties such as hardness, strength, fatigue resistance; 2) chemical properties such as corrosion resistance, catalysis; 3) thermal properties such as conductivity, insulation, coefficient of expansion; 4) magnetic properties such as ferro and para magnetism; and, 5) optical properties such as color and decoration. Most alloying is done in liquid state via melting and casting. However, for many applications, the property enhancement is necessary only at the surface level.
Metallic materials may also be surface hardened via carburizing, nitriding and boriding. Carburizing is accomplished by adding carbon to the surface layer by exposing the material to a carbon rich atmosphere at an elevated temperature to allow carbon diffusion. Carburizing is done at high temperature (900° C.). For nitriding, nitrogen is diffused into the surface of steel usually from ammonia (NH3) at about 600° C. temperature for 10-40 hours duration. Boriding is accomplished by diffusing boron into the surface and forming different iron boride layers on the surface. This is usually done in various boron containing environments at 900-1000° C. for 6-25 hours duration.
However, for many applications, processing such as alloying, carburizing, nitriding and boriding is needed only on the surface layer. Processing the surface often involves special equipment such as high temperature furnace and lasers at significant cost. Accordingly there is a need for a method for mechanically processing metallic material surfaces that is cost effective, efficient and does not require specialized equipment.